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The following commit(s) were added to refs/heads/master by this push:
new b70fc57849 RP2040 Board Documentation
b70fc57849 is described below
commit b70fc57849108f8d70613a902a288c52651ea7e1
Author: curuvar <58759586+curu...@users.noreply.github.com>
AuthorDate: Fri Jul 1 16:23:35 2022 -0400
RP2040 Board Documentation
---
.../boards/adafruit-feather-rp2040/Feather.png | Bin 0 -> 207962 bytes
.../boards/adafruit-feather-rp2040/index.rst | 209 +++++++++++++++++++++
.../arm/rp2040/boards/adafruit-kb2040/KB2040.png | Bin 0 -> 177093 bytes
.../arm/rp2040/boards/adafruit-kb2040/index.rst | 185 ++++++++++++++++++
.../rp2040/boards/pimoroni-tiny2040/Tiny2040.png | Bin 0 -> 127111 bytes
.../arm/rp2040/boards/pimoroni-tiny2040/index.rst | 127 +++++++++++++
.../boards/raspberrypi-pico/RaspberryPiPico.png | Bin 0 -> 229318 bytes
.../arm/rp2040/boards/raspberrypi-pico/index.rst | 203 ++++++++++++++++++++
Documentation/platforms/arm/rp2040/index.rst | 113 +++++++++++
9 files changed, 837 insertions(+)
diff --git
a/Documentation/platforms/arm/rp2040/boards/adafruit-feather-rp2040/Feather.png
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index 0000000000..c7972a8479
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b/Documentation/platforms/arm/rp2040/boards/adafruit-feather-rp2040/Feather.png
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diff --git
a/Documentation/platforms/arm/rp2040/boards/adafruit-feather-rp2040/index.rst
b/Documentation/platforms/arm/rp2040/boards/adafruit-feather-rp2040/index.rst
new file mode 100644
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--- /dev/null
+++
b/Documentation/platforms/arm/rp2040/boards/adafruit-feather-rp2040/index.rst
@@ -0,0 +1,209 @@
+=======================
+Adafruit Feather RP2040
+=======================
+
+The Feather RP2040 is a general purpose RP2040 board supplied by
+Adafruit.
+
+.. figure:: Feather.png
+ :align: center
+
+Features
+========
+
+* RP2040 microcontroller chip
+* Dual-core ARM Cortex M0+ processor, flexible clock running up to 133 MHz
+* 264kB of SRAM, and 8MB of on-board Flash memory
+* Castellated module allows soldering direct to carrier boards
+* USB Host and Device support via type C connector.
+* Low-power sleep and dormant modes
+* Drag & drop programming using mass storage over USB
+* 26 multi-function GPIO pins
+* 2× SPI, 2× I2C, 2× UART, 3× 12-bit ADC, 16× controllable PWM channels
+* Accurate clock and timer on-chip
+* Temperature sensor
+* Accelerated floating point libraries on-chip
+* 8 × Programmable IO (PIO) state machines for custom peripheral support
+* LiPoly Battery connector
+
+Serial Console
+==============
+
+By default a serial console appears on pins 14 (RX GPIO0) and pin 15
+(TX GPIO1). This console runs a 115200-8N1.
+
+The board can be configured to use the USB connection as the serial console.
+
+Buttons and LEDs
+================
+
+User LED controlled by GPIO13.
+
+A ws2812 (NeoPixel) smart RGB LED controlled by GPIO16.
+
+An LED (CHG LED) that indicates the charging status of
+connected LiPo cell.
+
+There is a BOOT button which if held down when power is first
+applied or the RESET button is pressed will cause the RP2040 to
+boot into program mode and appear as a storage device to
+a USB connecte . Saving a .UF2 file to this device will
+replace the Flash ROM contents on the RP2040.
+
+A RESET button that allows rebooting the board without disconnecting
+the power.
+
+Pin Mapping
+===========
+
+===== ========== ==========
+Pin Signal Notes
+===== ========== ==========
+1 Reset Pull to ground to reset the RP2040 processor.
+2 3.3V Power out to peripherals.
+3 3.3V Power out to peripherals.
+4 Ground
+5 GPIO26 ADC0
+6 GPIO27 ADC1
+7 GPIO28 ADC2
+8 GPIO29 ADC3
+9 GPIO24
+10 GPIO25
+11 GPIO18
+12 GPIO19
+13 GPIO20
+14 GPIO1 Default RX for UART1 serial console
+15 GPIO0 Default TX for UART0 serial console
+16 GPIO6
+17 GPIO2
+18 GPIO3
+19 GPIO7
+20 GPIO8
+21 GPIO9
+22 GPIO10
+23 GPIO11
+24 GPIO12
+25 GPIO13
+26 VBUS Connected to USB +5V
+27 EN Pull to ground to turn off 3.3V regulator.
+28 VBAT Connected to LiPo battery 3.3V.
+===== ========== ==========
+
+The board has a STEMMA QT connector that is also connected to
+pins GPIO2 (I2C1 SDA) and GPIO3 (I2C1 SDA).
+
+The board has a two pin JST PH socket that accepts a single 3.3V
+LiPo cell. The cell connected to this port can be charged by
+connecting the board to a USB power supply.
+
+There are solder pads on the board that allow the addition of
+a 10-pin serial debug (SWD) connector.
+
+Power Supply
+============
+
+The Raspberry Pi Pico can be powered via the USB connector,
+or by supplying +5V to pin 39. The board had a diode that prevents
+power from pin 39 from flowing back to the USB socket, although
+the socket can be power via pin 30.
+
+The Raspberry Pi Pico chip run on 3.3 volts. This is supplied
+by an onboard voltage regulator. This regulator can be disabled
+by pulling pin 37 to ground.
+
+The regulator can run in two modes. By default the regulator runs
+in PFM mode which provides the best efficiency, but may be
+switched to PWM mode for improved ripple by outputting a one
+on GPIO23.
+
+
+Configurations
+==============
+
+audiopack
+---------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with
+support for NSPlayer audio player.
+
+composite
+---------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+CDC/ACM with MSC USB composite driver.
+
+displaypack
+-----------
+
+NuttShell configuration (console enabled in USB Port, at 115200 bps) supporting
+ST7789 video display.
+
+enc28j60
+--------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+NC28J60.
+
+lcd1602
+-------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+LCD1602.
+
+nsh
+---
+
+Basic NuttShell configuration (console enabled in UART0, at 115200 bps).
+
+nshsram
+-------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with
interrupt
+vectors in RAM.
+
+smp
+---
+
+Basic NuttShell configuration (console enabled in UART0, at 115200 bps) with
+both ARM cores enabled.
+
+spisd
+-----
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with SPI
configured.
+
+ssd1306
+-------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+ssd1306.
+
+st7735
+------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+st7735.
+
+usbmsc
+------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+usbmsc.
+
+usbnsh
+------
+
+Basic NuttShell configuration (console enabled in USB Port, at 115200 bps).
+
+waveshare-lcd-1.14
+------------------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+st7789.
+
+waveshare-lcd-1.3
+-----------------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+usbmsc.
+
diff --git
a/Documentation/platforms/arm/rp2040/boards/adafruit-kb2040/KB2040.png
b/Documentation/platforms/arm/rp2040/boards/adafruit-kb2040/KB2040.png
new file mode 100644
index 0000000000..c16c67045a
Binary files /dev/null and
b/Documentation/platforms/arm/rp2040/boards/adafruit-kb2040/KB2040.png differ
diff --git
a/Documentation/platforms/arm/rp2040/boards/adafruit-kb2040/index.rst
b/Documentation/platforms/arm/rp2040/boards/adafruit-kb2040/index.rst
new file mode 100644
index 0000000000..546aa1bc48
--- /dev/null
+++ b/Documentation/platforms/arm/rp2040/boards/adafruit-kb2040/index.rst
@@ -0,0 +1,185 @@
+========================
+Adafruit KB2040 Key Boar
+========================
+
+The KB2040 Key Boar is a general purpose RP2040 board supplied by
+Adafruit.
+
+.. figure:: KB2040.png
+ :align: center
+
+Features
+========
+
+* RP2040 microcontroller chip
+* Dual-core ARM Cortex M0+ processor, flexible clock running up to 133 MHz
+* 264kB of SRAM, and 8MB of on-board Flash memory
+* Castellated module allows soldering direct to carrier boards
+* USB Host and Device support via type C connector.
+* Low-power sleep and dormant modes
+* Drag & drop programming using mass storage over USB
+* 18 multi-function GPIO pins
+* 2× SPI, 2× I2C, 2× UART, 3× 12-bit ADC, 16× controllable PWM channels
+* Accurate clock and timer on-chip
+* Temperature sensor
+* Accelerated floating point libraries on-chip
+* 8 × Programmable IO (PIO) state machines for custom peripheral support
+* On-board STEMMA QT connector for quick I2C connection.
+
+Serial Console
+==============
+
+By default a serial console appears on pins 1 (TX GPIO0) and pin 2
+(RX GPIO1). This console runs a 115200-8N1.
+
+The board can be configured to use the USB connection as the serial console.
+
+Buttons and LEDs
+================
+
+There is a BOOT button which if held down when power is first
+applied or the RESET button is pressed will cause the RP2040 to
+boot into program mode and appear as a storage device to
+a USB connecte . Saving a .UF2 file to this device will
+replace the Flash ROM contents on the RP2040.
+
+A RESET button that allows rebooting the board without disconnecting
+the power.
+
+A ws2812 (NeoPixel) smart RGB LED controlled by GPIO17.
+
+Pin Mapping
+===========
+
+===== ========== ==========
+Pin Signal Notes
+===== ========== ==========
+1 D+ Alternate USB data connection.
+2 GPIO0 Default TX for UART0 serial console
+3 GPIO1 Default RX for UART1 serial console
+4 Ground
+5 Ground
+6 GPIO2
+7 GPIO3
+8 GPIO4
+9 GPIO5
+10 GPIO6
+11 GPIO7
+12 GPIO8
+13 GPIO9
+14 GPIO10
+15 GPIO19
+16 GPIO20
+17 GPIO18
+18 GPIO26 ADC0
+19 GPIO27 ADC1
+20 GPIO28 ADC2
+21 GPIO29 ADC3
+22 Ground
+23 Raw Connected to USB +5V line
+24 D- Alternate USB data connection.
+===== ========== ==========
+
+The board has a STEMMA QT connector that is also connected to
+pins GPI12 (I2C1 SDA) and GPI13 (I2C1 SDA).
+
+
+Power Supply
+============
+
+The Raspberry Pi Pico can be powered via the USB connector,
+or by supplying +5V to pin 23.
+
+The Raspberry Pi Pico chip run on 3.3 volts. This is supplied
+by an onboard voltage regulator.
+
+Configurations
+==============
+
+audiopack
+---------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with
+support for NSPlayer audio player.
+
+composite
+---------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+CDC/ACM with MSC USB composite driver.
+
+displaypack
+-----------
+
+NuttShell configuration (console enabled in USB Port, at 115200 bps) supporting
+ST7789 video display.
+
+enc28j60
+--------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+NC28J60.
+
+lcd1602
+-------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+LCD1602.
+
+nsh
+---
+
+Basic NuttShell configuration (console enabled in UART0, at 115200 bps).
+
+nshsram
+-------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with
interrupt
+vectors in RAM.
+
+smp
+---
+
+Basic NuttShell configuration (console enabled in UART0, at 115200 bps) with
+both ARM cores enabled.
+
+spisd
+-----
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with SPI
configured.
+
+ssd1306
+-------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+ssd1306.
+
+st7735
+------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+st7735.
+
+usbmsc
+------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+usbmsc.
+
+usbnsh
+------
+
+Basic NuttShell configuration (console enabled in USB Port, at 115200 bps).
+
+waveshare-lcd-1.14
+------------------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+st7789.
+
+waveshare-lcd-1.3
+-----------------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+usbmsc.
+
diff --git
a/Documentation/platforms/arm/rp2040/boards/pimoroni-tiny2040/Tiny2040.png
b/Documentation/platforms/arm/rp2040/boards/pimoroni-tiny2040/Tiny2040.png
new file mode 100644
index 0000000000..24d0d2bb99
Binary files /dev/null and
b/Documentation/platforms/arm/rp2040/boards/pimoroni-tiny2040/Tiny2040.png
differ
diff --git
a/Documentation/platforms/arm/rp2040/boards/pimoroni-tiny2040/index.rst
b/Documentation/platforms/arm/rp2040/boards/pimoroni-tiny2040/index.rst
new file mode 100644
index 0000000000..7bb7f3fe96
--- /dev/null
+++ b/Documentation/platforms/arm/rp2040/boards/pimoroni-tiny2040/index.rst
@@ -0,0 +1,127 @@
+=================
+Pimoroni Tiny2040
+=================
+
+The Tiny2040 is a general purpose RP2040 board supplied by Pimoroni.
+
+.. figure:: Tiny2040.png
+ :align: center
+
+Features
+========
+
+* RP2040 microcontroller chip
+* Dual-core ARM Cortex M0+ processor, flexible clock running up to 133 MHz
+* 264kB of SRAM, and 2MB or 8MB of on-board Flash memory
+* Castellated module allows soldering direct to carrier boards
+* USB Host and Device support via type C connector
+* Low-power sleep and dormant modes
+* Drag & drop programming using mass storage over USB
+* 12 multi-function GPIO pins
+* 2× SPI, 2× I2C, 2× UART, 3× 12-bit ADC, 16× controllable PWM channels
+* Accurate clock and timer on-chip
+* Temperature sensor
+* Accelerated floating point libraries on-chip
+* 8 × Programmable IO (PIO) state machines for custom peripheral support
+
+Serial Console
+==============
+
+By default a serial console appears on pins 15 (RX GPIO0) and
+pin 16 (TX GPIO1). This console runs a 115200-8N1.
+
+The board can be configured to use the USB connection as the serial console.
+
+Buttons and LEDs
+================
+
+There is a single onboard RGB LED controlled by pins
+GPIO18 (red), GPIO19 (green), and GPIO20 (blue).
+
+The is a User/BOOT button readable as GPIO23. If held down when power
+is first applied the RP2040 will boot into program mode and appear to
+a computer connected via USB as a storage device. Saving
+a .UF2 file to this device will replace the Flash ROM contents
+on the RP2040.
+
+Pin Mapping
+===========
+
+===== ========== ==========
+Pin Signal Notes
+===== ========== ==========
+1 VBUS Connected to USB +5V
+2 Ground
+3 3V3 Out to peripherals
+4 GPIO29 ADC3
+5 GPIO28 ADC2
+6 GPIO27 ADC1
+7 GPIO26 ADC0
+8 Ground
+9 GPIO7
+10 GPIO6
+11 GPIO5
+12 GPIO4
+13 GPIO3
+14 GPIO2
+15 GPIO1 Default RX for UART0 serial console
+16 GPIO0 Default TX for UART0 serial console
+===== ========== ==========
+
+Power Supply
+============
+
+The Raspberry Pi Pico can be powered via the USB connector,
+or by supplying +5V to pin 1.
+
+The Raspberry Pi Pico chip run on 3.3 volts. This is supplied
+by an onboard voltage regulator.
+
+Configurations
+==============
+
+composite
+---------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+CDC/ACM with MSC USB composite driver.
+
+gpio
+--------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with GPIO
examples.
+
+nsh
+---
+
+Basic NuttShell configuration (console enabled in UART0, at 115200 bps).
+
+nshsram
+-------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with
interrupt
+vectors in RAM.
+
+smp
+---
+
+Basic NuttShell configuration (console enabled in UART0, at 115200 bps) with
+both ARM cores enabled.
+
+spisd
+-----
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with SPI
configured.
+
+usbmsc
+------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+usbmsc.
+
+usbnsh
+------
+
+Basic NuttShell configuration (console enabled in USB Port, at 115200 bps).
+
+
diff --git
a/Documentation/platforms/arm/rp2040/boards/raspberrypi-pico/RaspberryPiPico.png
b/Documentation/platforms/arm/rp2040/boards/raspberrypi-pico/RaspberryPiPico.png
new file mode 100644
index 0000000000..bb5579bd80
Binary files /dev/null and
b/Documentation/platforms/arm/rp2040/boards/raspberrypi-pico/RaspberryPiPico.png
differ
diff --git
a/Documentation/platforms/arm/rp2040/boards/raspberrypi-pico/index.rst
b/Documentation/platforms/arm/rp2040/boards/raspberrypi-pico/index.rst
new file mode 100644
index 0000000000..a5d24637fc
--- /dev/null
+++ b/Documentation/platforms/arm/rp2040/boards/raspberrypi-pico/index.rst
@@ -0,0 +1,203 @@
+===============================
+Raspberry Pi Pico
+===============================
+
+The `Raspberry Pi Pico
<https://www.raspberrypi.com/products/raspberry-pi-pico/>`_ is a general
purpose board supplied by
+the Raspberry Pi Foundation.
+
+.. figure:: RaspberryPiPico.png
+ :align: center
+
+Features
+========
+
+* RP2040 microcontroller chip
+* Dual-core ARM Cortex M0+ processor, flexible clock running up to 133 MHz
+* 264kB of SRAM, and 2MB of on-board Flash memory
+* Castellated module allows soldering direct to carrier boards
+* USB 1.1 Host and Device support
+* Low-power sleep and dormant modes
+* Drag & drop programming using mass storage over USB
+* 26 multi-function GPIO pins
+* 2× SPI, 2× I2C, 2× UART, 3× 12-bit ADC, 16× controllable PWM channels
+* Accurate clock and timer on-chip
+* Temperature sensor
+* Accelerated floating point libraries on-chip
+* 8 × Programmable IO (PIO) state machines for custom peripheral support
+
+Serial Console
+==============
+
+By default a serial console appears on pins 1 (TX GPIO0) and pin 2
+(RX GPIO1). This console runs a 115200-8N1.
+
+The board can be configured to use the USB connection as the serial console.
+
+Buttons and LEDs
+================
+
+User LED controlled by GPIO25.
+
+A BOOTSEL button, which if held down when power is first
+applied to the board, the cause the RP2040 to boot programming mode
+and appear to a computer connected via USB as a storage device.
+Saving a .UF2 file to this device will replace the Flash ROM contents
+on the RP2040.
+
+Pin Mapping
+===========
+
+===== ========== ==========
+Pin Signal Notes
+===== ========== ==========
+1 GPIO0 Default TX for UART0 serial console
+2 GPIO1 Default RX for UART1 serial console
+3 Ground
+4 GPIO2
+5 GPIO3
+6 GPIO4
+7 GPIO5
+8 Ground
+9 GPIO6
+10 GPIO7
+11 GPIO8
+12 GPIO9
+13 Ground
+14 GPIO10
+15 GPIO11
+16 GPIO12
+17 GPIO13
+18 Ground
+19 GPIO14
+20 GPIO15
+21 GPIO16
+22 GPIO17
+23 Ground
+24 GPIO18
+25 GPIO19
+26 GPIO20
+27 GPIO21
+28 Ground
+29 GPIO22
+30 Run
+31 GPIO26 ADC0
+32 GPIO27 ADC1
+33 AGND Analog Ground
+34 GPIO28 ADC2
+35 ADC_VREF
+36 3V3 Power output to peripherals
+37 3V3_EN Pull to ground to turn off.
+38 Ground
+39 VSYS +5V Supply to board
+40 VBUS Connected to USB +5V
+===== ========== ==========
+
+Separate pins for the Serial Debug Port (SDB) are available
+
+Power Supply
+============
+
+The Raspberry Pi Pico can be powered via the USB connector,
+or by supplying +5V to pin 39. The board had a diode that prevents
+power from pin 39 from flowing back to the USB socket, although
+the socket can be power via pin 30.
+
+The Raspberry Pi Pico chip run on 3.3 volts. This is supplied
+by an onboard voltage regulator. This regulator can be disabled
+by pulling pin 37 to ground.
+
+The regulator can run in two modes. By default the regulator runs
+in PFM mode which provides the best efficiency, but may be
+switched to PWM mode for improved ripple by outputting a one
+on GPIO23.
+
+Configurations
+==============
+
+audiopack
+---------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with
+support for NSPlayer audio player.
+
+composite
+---------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+CDC/ACM with MSC USB composite driver.
+
+displaypack
+-----------
+
+NuttShell configuration (console enabled in USB Port, at 115200 bps) supporting
+ST7789 video display.
+
+enc28j60
+--------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+NC28J60.
+
+lcd1602
+-------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+LCD1602.
+
+nsh
+---
+
+Basic NuttShell configuration (console enabled in UART0, at 115200 bps).
+
+nshsram
+-------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with
interrupt
+vectors in RAM.
+
+smp
+---
+
+Basic NuttShell configuration (console enabled in UART0, at 115200 bps) with
+both ARM cores enabled.
+
+spisd
+-----
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with SPI
configured.
+
+ssd1306
+-------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+ssd1306.
+
+st7735
+------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+st7735.
+
+usbmsc
+------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+usbmsc.
+
+usbnsh
+------
+
+Basic NuttShell configuration (console enabled in USB Port, at 115200 bps).
+
+waveshare-lcd-1.14
+------------------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+st7789.
+
+waveshare-lcd-1.3
+-----------------
+
+NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for
+usbmsc.
+
diff --git a/Documentation/platforms/arm/rp2040/index.rst
b/Documentation/platforms/arm/rp2040/index.rst
new file mode 100644
index 0000000000..138327a92d
--- /dev/null
+++ b/Documentation/platforms/arm/rp2040/index.rst
@@ -0,0 +1,113 @@
+========
+rp2040
+========
+
+The rp2040 is a dual core chip produced by the RaspberryPi Foundation that
+is based on ARM Cortex-M0+.
+
+Peripheral Support
+==================
+
+The following list indicates peripherals currently supported in NuttX:
+
+============== =====
+Peripheral Notes
+============== =====
+GPIO See Supported Boards documentation for available pins.
+UART GPIO 0 (UART0 TX) and GPIO 1 (UART0 RX) are used for the
console.
+I2C
+SPI
+DMAC
+PWM
+USB
+PIO RP2040 Programmable I/O
+IRQs
+DMA
+ws2812 Smart pixels (e.g. Neopixel)
+Flash ROM Boot
+SRAM Boot If Pico SDK is available a nuttx.uf2 file will be created
+BMP180 Requires I2C0
+INA219 Requires I2C0
+============== =====
+
+The Pico Display Pack (ST7789 LCD) and Pico Audio Pack (PCM5100A I2S DAC) are
+also available.
+
+Installation
+============
+
+1. Download Raspberry Pi Pico SDK::
+
+ git clone -b 1.1.2 https://github.com/raspberrypi/pico-sdk.git
+
+2. Set PICO_SDK_PATH environment variable::
+
+ export PICO_SDK_PATH=<absolute_path_to_pico-sdk_directory>
+
+3. Download NuttX and the companion applications. These must both be
+ contained in the same directory::
+
+ git clone https://github.com/apache/incubator-nuttx.git nuttx
+ git clone https://github.com/apache/incubator-nuttx-apps.git apps
+
+Building NuttX
+==============
+
+1. Change to NuttX directory::
+
+ cd nuttx
+
+2. Select a configuration. The available configurations
+ can be listed with the command::
+
+ ./tools/configure.sh -L
+
+3. Load the selected configuration.::
+
+ make distclean
+ ./tools/configure.sh <selected_configuration>
+
+4. Modify the configuration as needed (optional)::
+
+ make menuconfig
+
+5. Build NuttX::
+
+ make
+
+Programming
+============
+
+Programming using BOOTSEL
+-------------------------
+
+Connect board to USB port while pressing BOOTSEL.
+The board will be detected as USB Mass Storage Device.
+Then copy "nuttx.uf2" into the device.
+(Same manner as the standard Pico SDK applications installation.)
+
+Programming using SDB
+---------------------
+
+Most (but no all) RP2040 boards provide a serial (SDB) debug port.
+The "nuttx" ELF file can be uploaded with an appropriate SDB programmer
+module and companion software.
+
+Running NuttX
+=============
+
+Most builds provide access to the console via UART0. To access this
+GPIO 0 and 1 pins must be connected to the device such as USB-serial converter.
+
+The `usbnsh` configuration provides the console access by USB CDC/ACM serial
+devcice. The console is available by using a terminal software on the USB
host.
+
+Supported Boards
+================
+
+.. toctree::
+ :glob:
+ :maxdepth: 1
+
+ boards/*/*
+
